TWI856925B - Optical sensor - Google Patents

Abstract

An optical sensor includes a substrate, a gate line, a data line, a thin film transistor, an optical sensor structure, a common electrode line and a first shading layer. The gate line is located over the substrate. The data line is located over the substrate. The gate of the thin film transistor connects to the gate line. The drain of the thin film transistor connects to the data line. A bottom electrode of the optical sensor structure is electrically connected to a source of the thin film transistor. The common electrode line is located over the substrate. The common electrode line is electronically connected to the top electrode of the light sensor structure. The first shading layer is located on the substrate. A top surface of the first shading layer is lower than a top layer of the light sensor structure. In the top view, at least a part of the first shading layer is located between the data line and the light sensor structure.

Description

Light sensor

The present disclosure relates to a light sensor.

Photo sensors are commonly used in electronic devices such as smartphones, laptops, or tablets. In addition, photo sensors are also used in medical diagnostic tools. For example, an X-ray sensor configured to receive X-rays can convert X-rays that pass through human tissue into visible images. How to come up with a photo sensor that can improve the quality of images is one of the problems that the industry is eager to invest in research and development resources to solve.

In view of this, an object of the present disclosure is to provide a light sensor that can effectively solve the above-mentioned problems.

The present disclosure relates to a photo sensor including a substrate, a gate line, a data line, a thin film transistor, a photosensitive structure, a common electrode line and a first light shielding layer. The gate line is located on the substrate. The data line is located on the substrate. The gate of the thin film transistor is electrically connected to the gate line. The drain of the thin film transistor is electrically connected to the data line. The lower electrode of the photosensitive structure is electrically connected to the source of the thin film transistor. The common electrode line is located on the substrate. The common electrode line is electrically connected to the upper electrode of the photosensitive structure. The first light shielding layer is located on the substrate. The upper surface of the first light shielding layer is lower than the upper surface of the photosensitive structure. From a top view, the first light shielding layer is at least partially located between the data line and the photosensitive structure.

In some current implementations, the first light shielding layer and the channel region of the thin film transistor have the same semiconductor material.

In some current implementations, the photo sensor further includes an extended electrode. The extended electrode extends from the drain of the thin film transistor to below the data line. A portion of the data line extends downward to contact the extended electrode. The extended electrode at least partially covers the first light shielding layer. The lower electrode of the photo sensing structure at least partially covers the first light shielding layer.

In some current implementations, the bottom electrode of the light sensing structure at least partially covers the first light shielding layer.

In some current implementations, the lower electrode of the light sensing structure is separated from the first light shielding layer.

In some current implementations, the bottom electrode of the light sensing structure at least partially covers the first light shielding layer.

In some current implementations, the lower electrode of the light sensing structure at least partially covers the first light shielding layer, and the light sensor further includes an extended electrode and a second light shielding layer. The extended electrode extends from the drain of the thin film transistor to below the data line. A portion of the data line extends downward to contact the extended electrode. The extended electrode at least partially covers the second light shielding layer. The first light shielding layer is separated from the second light shielding layer.

In some current implementations, the first light shielding layer, the second light shielding layer, and the channel region of the thin film transistor have the same semiconductor material.

In some current implementations, the photo sensor further includes an extended electrode. The extended electrode extends from the drain of the thin film transistor to below the data line. A portion of the data line extends downward to contact the extended electrode. The extended electrode is separated from the first light shielding layer. The lower electrode of the photo sensing structure is also separated from the first light shielding layer.

In some current implementations, the light sensor further includes a reflective layer located under the substrate.

In summary, in some embodiments of the photo sensor disclosed herein, the first light shielding layer, the second light shielding layer, and the channel region of the thin film transistor are formed in a single process using the same material, thereby further simplifying the process and the structure of the photo sensor. The first light shielding layer and the second light shielding layer are appropriately allocated to cover different regions of the photo sensor to reduce the light from each region of the photo sensor being reflected back into the interior of the photo sensor by the substrate, thereby affecting the sensing result of the photo sensor. The first light shielding layer, the second light shielding layer, the thin film transistor, and the photosensitive structure are appropriately separated to prevent the first light shielding layer and the second light shielding layer from forming a leakage path inside the photo sensor. A reflective layer, a first light shielding layer and a second light shielding layer are arranged on the light sensor to ensure that the sensing result of the light sensor is not affected by the reflected light.

The following disclosure provides many different embodiments or examples for implementing the different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify some embodiments of the present disclosure. Of course, these are only examples and are not intended to be restrictive. For example, in the following description, a first feature formed on or on a second feature may include an embodiment in which the first feature and the second feature are formed to be in direct contact, and may also include an embodiment in which an additional feature may be formed between the first feature and the second feature so that the first feature and the second feature may not be in direct contact. In addition, component symbols and/or letters may be repeated in various examples of the present disclosure. This repetition is for simplification and clarity purposes, and does not itself represent the relationship between the various embodiments and/or configurations discussed.

It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to another element, or intermediate elements may also exist. Conversely, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intermediate elements. As used herein, "connected" may refer to physical and/or electrical connections. Furthermore, "electrically connected" or "coupled" may mean that there are other elements between two elements.

As used herein, "about", "approximately", or "substantially" includes the stated value and the average value within an acceptable deviation range of a particular value determined by a person of ordinary skill in the art, taking into account the measurement in question and the particular amount of error associated with the measurement (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or within ±30%, ±20%, ±10%, ±5%. Furthermore, as used herein, "about", "approximately", or "substantially" can select a more acceptable deviation range or standard deviation depending on the optical property, etching property or other property, and can apply to all properties without using a single standard deviation.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by ordinary technicians in the field to which the present invention belongs. It will be further understood that those terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and the present invention, and will not be interpreted as an idealized or overly formal meaning unless expressly defined as such in this document.

FIG. 1A is a schematic diagram of a photo sensor 100 according to some embodiments of the present disclosure. FIG. 1B is a cross-sectional side view according to line segment B-B’ in FIG. 1A. FIG. 1C is a cross-sectional side view according to line segment C-C’ in FIG. 1A. Referring to FIG. 1A, FIG. 1B and FIG. 1C, a photo sensor 100 includes a substrate 110, a gate line 120, a data line 130, a thin film transistor 140, a photosensitive structure 150, a common electrode line 160 and a first light shielding layer 170. The gate line 120 is located on the substrate 110. The data line 130 is located on the substrate 110. The gate 142 of the thin film transistor 140 is electrically connected to the gate line 120. The drain 148 of the thin film transistor 140 is electrically connected to the data line 130. The lower electrode 152 of the photosensitive structure 150 is electrically connected to the source 144 of the thin film transistor 140. The common electrode line 160 is located on the substrate 110. The common electrode line 160 is electrically connected to the upper electrode 156 of the photosensitive structure 150. The first light shielding layer 170 is located on the substrate 110. The upper surface 170a of the first light shielding layer 170 is lower than the upper surface 150a of the photosensitive structure 150. From a top view, the first light shielding layer 170 is at least partially located between the data line 130 and the photosensitive structure 150. Specifically, the data line 130, the thin film transistor 140, the photosensitive structure 150 and the common electrode line 160 can be separated by an insulating layer (for example, the insulating layers 192 and 194 in FIG. 1B or 1C), and an insulating layer (for example, the insulating layer 196 in FIG. 1B or 1C) can also be covered on the data line 130, the thin film transistor 140, the photosensitive structure 150 and the common electrode line 160 or other structures can be formed.

1A, 1B and 1C, a gate line 120 and a data line 130 are disposed on a substrate 110. In the embodiment shown in FIG. 1A, the gate line 120 extends longitudinally, and the data line 130 extends transversely and overlaps a portion of the gate line 120. In the embodiment of FIG. 1B, the data line 130 has a through hole, which passes through the insulating layer 192 and the insulating layer 194 and extends downward. In some embodiments, the photo sensor 100 further includes an extended electrode 180. Referring to FIG. 1A, the extended electrode 180 extends from the drain 148 of the thin film transistor 140 to below the data line 130. 1B , the through hole of the data line 130 extends downward and contacts the extension electrode 180 . The extension electrode 180 at least partially covers the first light shielding layer 170 . On the other hand, the lower electrode 152 of the light sensing structure 150 also at least partially covers the first light shielding layer 170 .

Referring to FIG. 1A, FIG. 1B and FIG. 1C, a thin film transistor 140 and a light sensing structure 150 are also disposed on the substrate 110. The thin film transistor 140 is disposed adjacent to the gate line 120 and its gate 142 extends laterally to be electrically connected to the gate line 120 (see FIG. 1A). The source 144 and the drain 148 of the thin film transistor 140 extend longitudinally and are connected to the light sensing structure 150 and the data line 130, respectively. At the same time, the common electrode line 160 disposed on the substrate 110 is parallel to the data line 130 and extends laterally across the gate line 120 and the light sensing structure 150. 1B and 1C, the photosensitive structure 150 has an upper electrode 156 and a photosensitive layer 154 located between the lower electrode 152 and the upper electrode 156. Specifically, the lower electrode 152 of the photosensitive structure 150 is disposed above the substrate 110. The insulating layer 192 is disposed above the lower electrode 152 of the photosensitive structure 150, wherein the insulating layer 192 has a through hole 192H, and the through hole 192H exposes a portion of the surface of the lower electrode 152. The photosensitive layer 154 is filled in the through hole 192H and directly contacts the portion of the surface of the lower electrode 152 exposed by the through hole 192H to form an electrical connection. The upper electrode 156 of the photo-sensing structure 150 is directly in contact with and disposed on the photo-sensing layer 154. The common electrode line 160 is provided with a through hole extending downward and is electrically connected to the upper electrode 156 of the photo-sensing structure 150.

Please refer to FIG. 1A, FIG. 1B and FIG. 1C. In some embodiments, the first light shielding layer 170 partially covered by the extended electrode 180 is further extended and located in the area below the through hole of the data line 130, the area between the data line 130 and the light sensing structure 150, and the area below the light sensing structure 150. Furthermore, in some embodiments, the lower electrode 152 of the light sensing structure 150 at least partially covers the first light shielding layer 170. It can be seen from FIG. 1B and FIG. 1C that the light sensing structure 150 will be completely disposed above the first light shielding layer 170, and the upper surface 150a of the light sensing structure 150 is higher than the upper surface 170a of the first light shielding layer 170. 1A , it can be seen from a top view that the area of the first light shielding layer 170 is larger than the area of the lower electrode 152 of the light sensing structure 150 .

At the same time, the first light shielding layer 170 overlaps with a portion of the gate line 120 and the data line 130, respectively, but does not extend beyond the other edge of the gate line 120 or the data line 130. In other words, the covering area of the first light shielding layer 170 will not extend to another adjacent pixel unit. Since the material used for the data line 130 and the gate line 120 is a light-proof material (for example, metal), by overlapping the first light shielding layer 170 with a portion of the data line 130 and the gate line 120, it is ensured that there is no uncovered light-transmitting area between the first light shielding layer 170 and the data line 130 and the gate line 120. The first light shielding layer 170 can reduce the light reflected by the substrate 110 to a certain extent (for example, reduce the light reflectivity by about 40%). In this way, covering the first light shielding layer 170 can reduce the light reflectivity of the photo sensor 100 in the data line 130, the thin film transistor 140 and the light sensing structure 150, so as to reduce the influence of the reflected light on the judgment result of the light sensing structure 150.

Please refer to FIG. 1A and FIG. 1C , the channel region 146 of the thin film transistor 140 is located between the source 144 and the drain 148. A gate 142 is provided below the channel region 146, and the gate 142 is controlled by controlling the signal applied to the gate line 120 to further open or close the channel region 146 of the thin film transistor 140. In some embodiments, the first light shielding layer 170 and the channel region 146 of the thin film transistor 140 have the same semiconductor material. Because the first light shielding layer 170 and the channel region 146 are composed of the same semiconductor material, they can be formed in the same process. In some embodiments, the material used to form the first light shielding layer 170 and the channel region 146 can be or include amorphous silicon. However, in other embodiments, other suitable materials can also be used. The same material used to form the first light shielding layer 170 and the channel region 146 can simplify the manufacturing steps of the photo sensor 100 and reduce the reflectivity of the photo sensor 100.

In the embodiment where the first light shielding layer 170 of the photo sensor 100 is a semiconductor material, since leakage current may be generated in the area where the first light shielding layer 170 is laid, the covering area of the first light shielding layer 170 does not extend to another adjacent pixel unit. In this way, leakage current can be avoided between pixel units through the first light shielding layer 170.

FIG. 2A is a schematic diagram of a photo sensor 100 according to other embodiments of the present disclosure. FIG. 2B is a cross-sectional side view according to line segment B-B’ in FIG. 2A. FIG. 2C is a cross-sectional side view according to line segment C-C’ in FIG. 2A. Referring to FIG. 2A, FIG. 2B and FIG. 2C, compared to the aforementioned embodiments for FIG. 1A, FIG. 1B and FIG. 1C, the first light shielding layer 170 is located in the area between the data line 130 and the photo sensing structure 150 and in the area below the photo sensing structure 150, but is not in direct contact with the extended electrode 180 (or, the first light shielding layer 170 is separated from the extended electrode 180). Since the first light shielding layer 170 is not in direct contact with the extended electrode 180, leakage current can be avoided between the extended electrode 180 and the lower electrode 152 of the light sensing structure 150 through the first light shielding layer 170. As for other elements and details, they are the same as those in the embodiments of FIG. 1A, FIG. 1B and FIG. 1C, and will not be repeated.

FIG. 3A is a schematic diagram of a photo sensor 100 according to other embodiments of the present disclosure. FIG. 3B is a cross-sectional side view according to line segment B-B’ in FIG. 3A. FIG. 3C is a cross-sectional side view according to line segment C-C’ in FIG. 3A. Referring to FIG. 3A, FIG. 3B and FIG. 3C, compared to the aforementioned embodiments for FIG. 1A, FIG. 1B and FIG. 1C, the first light shielding layer 170 is located in the area below the through hole of the data line 130 and in the area between the data line 130 and the photo sensing structure 150, but is not in direct contact with the lower electrode 152 of the photo sensing structure 150 (or, the first light shielding layer 170 is separated from the lower electrode 152 of the photo sensing structure 150). Since the first light shielding layer 170 does not directly contact the lower electrode 152 of the light sensing structure 150, leakage current between the extended electrode 180 and the lower electrode 152 of the light sensing structure 150 through the first light shielding layer 170 can be avoided. As for other elements and details, they are the same as those in the embodiments of FIG. 1A, FIG. 1B and FIG. 1C, and will not be repeated.

FIG. 4A is a schematic diagram of a photo sensor 100 according to other embodiments of the present disclosure. FIG. 4B is a cross-sectional side view according to line segment B-B' in FIG. 4A. FIG. 4C is a cross-sectional side view according to line segment C-C' in FIG. 4A. Referring to FIG. 4A, FIG. 4B and FIG. 4C, compared with the aforementioned embodiments of FIG. 1A, FIG. 1B and FIG. 1C, the first light shielding layer 170 only covers the area between the data line 130 and the photo sensing structure 150. The first light shielding layer 170 does not directly contact the extended electrode 180 (or, the first light shielding layer 170 is separated from the extended electrode 180), nor does it directly contact the lower electrode 152 of the photo-sensing structure 150 (or, the first light shielding layer 170 is separated from the lower electrode 152 of the photo-sensing structure 150). Since the first light shielding layer 170 does not directly contact the extended electrode 180 and the lower electrode 152 of the photo-sensing structure 150, leakage current can be avoided between the extended electrode 180 and the lower electrode 152 of the photo-sensing structure 150 through the first light shielding layer 170. As for other components and details, they are the same as the embodiments of FIG. 1A, FIG. 1B and FIG. 1C, and will not be repeated.

FIG. 5A is a schematic diagram of a photo sensor 100 according to other embodiments of the present disclosure. FIG. 5B is a cross-sectional side view according to line segment B-B' in FIG. 5A. FIG. 5C is a cross-sectional side view according to line segment C-C' in FIG. 5A. Referring to FIG. 5A, FIG. 5B and FIG. 5C, in addition to the several embodiments discussed above in which the first light shielding layer 170 is provided, multiple unconnected light shielding layers may also be provided to achieve the purpose of avoiding leakage current. In some embodiments, the first light shielding layer 170 and the second light shielding layer 172 are provided in the photo sensor 100. In some embodiments, the lower electrode 152 of the photosensitive structure 150 at least partially covers the first light shielding layer 170, and the extended electrode 180 at least partially covers the second light shielding layer 172. The first light shielding layer 170 is separated from the second light shielding layer 172. In other words, the first light shielding layer 170 and the second light shielding layer 172, which are respectively disposed in the photosensor 100, are not connected to each other. The first light shielding layer 170 partially overlaps with the lower electrode 152 of the photosensitive structure 150, and is used to shield a portion of the area between the data line 130 and the photosensitive structure 150 and the area below the photosensitive structure 150. The second light shielding layer 172 partially overlaps with the extended electrode 180 and is used to shield the area below the through hole of the data line 130 and part of the area between the data line 130 and the light sensing structure 150. At the same time, the first light shielding layer 170 and the second light shielding layer 172 overlap with the gate line 120 and the data line 130 respectively, but do not extend beyond the other edge of the gate line 120 or the data line 130. On the other hand, in the cross-sectional view of FIG. 5B and FIG. 5C, the upper surface 170a of the first light shielding layer 170 and the upper surface 172a of the second light shielding layer 172 are both lower than the upper surface 150a of the light sensing structure 150.

In some embodiments, the first light shielding layer 170, the second light shielding layer 172 and the channel region 146 of the thin film transistor 140 have the same semiconductor material. Specifically, please refer to FIG. 5C. Since the first light shielding layer 170, the second light shielding layer 172 and the channel region 146 of the thin film transistor 140 (located between the source 144 and the drain 148) are composed of the same semiconductor material, they can be formed in the same process. In some embodiments, the material used to form the first light shielding layer 170, the second light shielding layer 172 and the channel region 146 can be or include amorphous silicon. However, in other embodiments, other suitable materials can also be used. The same material used to form the first light shielding layer 170, the second light shielding layer 172 and the channel region 146 can simplify the manufacturing steps of the photo sensor 100 and reduce the reflectivity of the photo sensor 100. In the embodiment where the first light shielding layer 170 and the second light shielding layer 172 are made of semiconductor materials, since leakage current may be generated in the area where the first light shielding layer 170 and the second light shielding layer 172 are laid, the first light shielding layer 170 and the second light shielding layer 172 can be separated from each other to avoid leakage current problems. As for other components and details, they are the same as the embodiments of FIG. 1A, FIG. 1B and FIG. 1C, and will not be repeated.

FIG. 6 is a schematic diagram of a photo sensor 100 according to other embodiments of the present disclosure. Referring to FIG. 6 , compared to the aforementioned embodiments of FIG. 1A , FIG. 1B , and FIG. 1C , the photo sensor 100 of FIG. 6 further includes a reflective layer 200 located under the substrate 110 . Specifically, the photo sensor 100 can be used in conjunction with the reflective layer 200 . In some embodiments, the reflective layer 200 is disposed under the substrate 110 and can be fixed to the substrate 110 by gluing. When the photo sensor 100 is provided with a light shielding layer (e.g., a first light shielding layer 170 ) and a reflective layer 200 at the same time, the reflected light of the photo sensor 100 can be further reduced to ensure that the sensing result of the photo sensor 100 is not affected by the reflected light. As for other components and details, they are the same as those in the embodiments of FIG. 1A , FIG. 1B and FIG. 1C , and will not be described again. In addition, the photo sensor 100 of the other embodiments can also be used with the reflective layer 200 in a similar configuration.

From the above detailed description of the specific implementation methods of the present disclosure, it can be clearly seen that in the photosensors of some embodiments of the present disclosure, the first light shielding layer and the channel area of the thin film transistor are formed in a single process using the same material, thereby further simplifying the process and the structure of the photosensor. The first light shielding layer is appropriately covered with different areas of the photosensor to reduce the light from each area of the photosensor being reflected back into the interior of the photosensor by the substrate, causing the sensing result of the photosensor to be affected. The first light shielding layer, the thin film transistor and the photosensitive structure are appropriately separated to prevent the first light shielding layer from forming a leakage current path inside the photosensor. A reflective layer and the first light shielding layer are arranged on the photosensor to ensure that the sensing result of the photosensor is not affected by the reflected light.

The foregoing summarizes the features of several embodiments so that those skilled in the art can better understand the aspects of the present disclosure. Those skilled in the art should understand that they can easily use the present disclosure as a basis for designing or modifying other processes and structures for achieving the same purpose and/or achieving the same advantages of the embodiments described herein. Those skilled in the art should also recognize that these equivalent structures do not depart from the spirit and scope of the present disclosure, and that they can make various changes, substitutions and replacements herein without departing from the spirit and scope of the present disclosure.

100: photo sensor 110: substrate 120: gate line 130: data line 140: thin film transistor 142: gate 144: source 146: channel region 148: drain 150: photo sensing structure 150a: upper surface 152: lower electrode 154: photo sensing layer 156: upper electrode 160: common electrode line 170,172: light shielding layer 170a,172a: upper surface 180: extension electrode 192,194,196: insulating layer 192H: through hole 200: reflective layer B-B’,C-C’: line segment

The present disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, in accordance with standard industry practice, the various features are not drawn to scale. In fact, the sizes of the various features may be arbitrarily increased or decreased for clarity of discussion. FIG. 1A is a schematic diagram of a photo sensor according to some embodiments of the present disclosure. FIG. 1B is a cross-sectional side view according to line segment B-B’ in FIG. 1A. FIG. 1C is a cross-sectional side view according to line segment C-C’ in FIG. 1A. FIG. 2A is a schematic diagram of a photo sensor according to other embodiments of the present disclosure. FIG. 2B is a cross-sectional side view according to line segment B-B’ in FIG. 2A. FIG. 2C is a cross-sectional side view according to line segment C-C’ in FIG. 2A. FIG. 3A is a schematic diagram of a photo sensor according to other embodiments of the present disclosure. FIG. 3B is a cross-sectional side view according to line segment B-B’ in FIG. 3A. FIG. 3C is a cross-sectional side view according to line segment C-C’ in FIG. 3A. FIG. 4A is a schematic diagram of a photo sensor according to other embodiments of the present disclosure. FIG. 4B is a cross-sectional side view according to line segment B-B’ in FIG. 4A. FIG. 4C is a cross-sectional side view according to line segment C-C’ in FIG. 4A. FIG. 5A is a schematic diagram of a photo sensor according to other embodiments of the present disclosure. FIG. 5B is a cross-sectional side view according to line segment B-B’ in FIG. 5A. FIG. 5C is a cross-sectional side view according to line segment C-C' in FIG. 5A. FIG. 6 is a schematic diagram of a photo sensor according to other embodiments of the present disclosure.

Domestic storage information (please note in the order of storage institution, date, and number) None Foreign storage information (please note in the order of storage country, institution, date, and number) None

100: Light sensor

110: Substrate

120: Gate line

130: Data line

140: Thin Film Transistor

142: Gate

144: Source

148: Drainage

150: Light sensing structure

152: Lower electrode

154: Light-sensing layer

156: Upper electrode

160: Common electrode line

170: Shading layer

180: Extended electrode

192H:Through hole

B-B’,C-C’: line segment

Claims (7)

A photo sensor comprises: a substrate; a gate line located on the substrate; a data line located on the substrate; a thin film transistor, a gate of the thin film transistor being electrically connected to the gate line, and a drain of the thin film transistor being electrically connected to the data line; a photosensitive structure, a lower electrode of the photosensitive structure being electrically connected to a source of the thin film transistor; a common electrode line located on the substrate and electrically connected to an upper electrode of the photosensitive structure; and a first light shielding layer located on the substrate, an upper surface of the first light shielding layer being lower than an upper surface of the photosensitive structure, and in a top view, the first light shielding layer is at least partially located between the data line and the photosensitive structure, The lower electrode of the light sensing structure at least partially covers the first light shielding layer. The photo sensor as described in claim 1 further comprises: A reflective layer located under the substrate. The photo sensor as described in claim 1 further comprises: An extended electrode extending from the drain of the thin film transistor to below the data line, and a portion of the data line extending downward to contact the extended electrode. A photosensor as described in claim 3, wherein the extended electrode at least partially covers the first light-shielding layer. A photosensor as described in claim 3, wherein the extended electrode is separated from the first light shielding layer. The photo sensor as described in claim 3 further comprises: A second light shielding layer, wherein the extended electrode at least partially covers the second light shielding layer, and the first light shielding layer is separated from the second light shielding layer. A photosensor as described in claim 6, wherein the first light-shielding layer, the second light-shielding layer and a channel region of the thin film transistor have the same semiconductor material.